Vertical lift bridge construction



Fell 3, 1942- B. R. LEFFLER' Er-AL 2,271,697

VERTICAL LIFT BRIDGE GGNSTRUCTION Filed May 2, 1939 5 Sheets-Sheet 1 @fwn ATTORNEY.

Feb. 3, 1942. BQR, LEFFLER ETAL 2,271,697

VERTICAL LIT BRIDGE CONSTRUCTION Filed May 2, 1939 3 Sheets-Sheet 2 l 2 v ZZ T y ad BY @NV I czzf jaelarrz/ Feb 3, 1942- B. R. LEFFLER ETAL VERTICAL LIFT BRIDGE CONSTRUCTIN Filed-May 2, 1939 3 Sheets-Sheet 3 Patented Feb. 3, 1942 VERTICAL LIFT BRIDGE CONSTRUCTION Burton a. Lerner, cleveland, ohio, and Clifford E. Paine,.La Grange,'llll.; said Leflier assigner to saidl Paine Application May 2, 1939, Serial No. 271,370

(Cl. lli-42) 10 Claims.

This invention relatesvr to vertical lift bridge construction and aims to provide an improved construction with enhanced eciency of operation and maintenance.

lIn bridges of this class which are moved by a vertical translatory motion asis desirable in many locations particularly on railroads, diiiculties have been encountered in securing true rectilinear movement of the lift span, without canting which would be highly undesirable, both as causing excessive wear on the bridge parts and also unsatisfactory seating of the lift span in normal position. The present construction has been found to eliminate these difliculties in a marked degree and with accompanying enhanced strength, simplicity and economyy of parts while rendering the operation more certain and. dependable.

Other objects and advantages will be apparent from the following description, taken together with the accompanying drawings, in which-.-

Figure 1 is a generalside elevational View of one end of a bridge construction embodying the present invention;

Figure 1a is a similar view of the other end of said bridge;

Figure 2 is a side elevational View of parts of the structure on a somewhat larger scale, taken on the line 2-2 of Fig. 3;

Figure 3 is a front elevational View of the portion of the structure of Fig. 2 on a still larger scale, parts being shown in section;

Figure 3a is `an axial sectional more detailed view on a still larger scale of the sheave bearings shown more generally in Fig. 3;

Figure 4 is a somewhat still further enlarged view of a counterweight group constituted in accordance with the present invention with the various counterweights shown in stepped-off sections for clearness of description; and y Figure 4a is an elevational view of the cable socket and pin employed with the construction of Fig. 4.

Referring in detail to the illustrative construction shown in the drawings, the piers I and II may be of the usual concrete formation and on opposite sides of a navigable waterway, say, which is desired to be spanned by the bridge which has the vertically extending towers I2 and I3 and the vertically movable horizontal lift span I4, the towers being fixed in the usual Way on the concrete piers I0 andl II and the span I4 being carried by and movable on the towers While .the span is being raised, the latter being othervwise also supported by the piers I0 and II as by chairs I5 and I6. It will be understoodr that there are two of the chairs I5 and two ofthe chairs IS at opposite ends of the bridge and that it is desirable when the bridge is in normal positionto have the chairs I5 and I6 all seat on the piers to insure a proper position of the span with respect to the roadway which passes through the open framework at the bases of the towers and is continued through the open frame Work on the span, the roadbed itself'being in the vicinity of the lower chords I'I of the lift span.

The towers I2 and .I3 serve not only as supports and guides for the lift span but also as supports and guides for the counterweights I8 by which the weight of the span is equalized so that the span may be raised by a minimum expenditure of energy. lA plurality vof cab-les I9 at each end of the bridge have ends thereof iixedly secured to thevspan as at 20 and then pass upwardly over devices such as the sheaves 2| or 22 which change the direction of the cables and from which the free ends of the latter depend and are secured as at 23 to the counterweights.

In accordance with the present invention, at least less than half of the cables at `one end of the span have independent counterweights attached thereto, by which is meant that rat each end of thespan the cables are not all attached to the same counterweight and desirably, as here shown, each cablev has its individual counterweight which in gravitational response is substantially independent of every other counterweight while at the Sametime the counterweights `advantageously have common means preventing substantial lateral movement of the individual counterweights but permitting individual vertical movement.

So counterbalanced, the span may be readily raised or lowered by the torque eiect of rotation of pinions-M and 25 carried by the lift span and engaging racks 26 andf2'l respectively carried by the towers, there being interengaging guiding means on the towers and span for preventing lateral movement of the span While at the same time permitting slight limited longitudinalmovement of the span at one end to accommodate variations in the length of the span due to expansion or contraction of the material thereof.

In accordance withv the preferred construction, the racks. 26 and 2l are each locatedl in a vertical plane passing vthrough the longitudinal center line of the span and these racks are so constructed as to serve also as guides engaged by guide rollers attached to the lift span and located approximately in lthe -plane of the top chords 28 of the span. Other guides are provided by the corner posts 29 and 30 of each tower engaged by shoes 3| and 32 respectively carried by the span in the vicinity of the lower chords I'I of the span. This arrangement provides a triangular or three-point guiding means at each end of the span, the apex of the triangle so defined being in the longitudinal center plane of the span, and adjacent the upper chords thereof, whereas the base of the triangle has its corners at the corner posts of the tower and in the region of the lower chords of the span, as is well known in the art.

Means for rotating the pinions 24 and 25 to actuate vertical movement of the span may be provided by motor mechanism suitably protected from the weather by a shed 50 carried by the upper chords 28 of the span and driving the pinions through a shaft 48 comprising suitable speed reduction means.

Turning now to the counterweight system, as already referred to, in accordance with the present invention and as best understood from Figs. 2 and 3, as here shown, each of the cablesv I9 passes over an individual sheave 2| or 22 as the case may be, and has attached thereto an individual counterweight I8. At this point it may be mentioned that one advantage of the present invention is that the individual sheaves may be desirably staggered to save space, in this case some of the cables I9 passing over the lower row of sheaves 2| and others passing over the upper row 22, but there being otherwise no difference in the construction, function and operation of the sheaves, cables and counterweights. It will be understood that the rows of sheaves 2| and 22 respectively are carried in each instance by the adjacent tower cross struts 18 as next described.

As here shown, in order further to save space, the sheaves are mounted in pairs, each pair having a common axle 19, as best shown in Fig. 3a. This short axle, one for each pair of sheaves, is carried as here shown, by a pair of semi-cylindrical bearings 80 to which the axle is keyed as at 8|. Before the axle is set into the bearings 80 it has passed thereonto a transversely split bushing having the outwardly flanged bushing sections 82 upon one of each of which is pressed a sheave through its hub 83. of the combined bushing sections 82 is such that they are received with a snug rotative fit between bearings 80 and these bearings cooperate with the anges of the bushing sections to prevent axial movement of the sheaves on their axle, the

inner unflanged ends of the bushing sections I abutting with a free running fit at the center of the axle and the hubs of the sheaves of a pair having suitable play therebetween to permit independent rotation of each sheave of a pair and its individual bushing section on their common axle. The bushing sections 82, for example, may be of bronze and the axle 19 of polished steel, to provide a good sliding contact with a minimum of friction, or, if desired, ball or roller bearings or other anti-friction devices may be employed. These bearings may be lubricated, for example, by conduits 84 Icarried by the web 85 of the sheave each having a mouth at the periphery of the sheave and communicating at their inner end with a duct 86 in the hub of the sheave, which may be continued through the bushing, and the axle 'I9 may have suitable lubrication grooves therein as at 81.

The pairs of bearings 80 may be suitably mounted on vertical supports 88 which project The axial length upwardly from and are suitably secured at one end to the cross struts 'I8 of the tower structure, the pair of sheaves thus turning not only between the bearings but also between the vertical supports, these being of a sufficient height to clear the sheaves above the cross struts. Horizontal reinforcing cross struts 89 between the vertical supports strengthen the supports 89 and bearings 80 against lateral stresses.

The connections of the free ends of the cables to the counterweights are shown in detail in Figs. 4 and 4a. The cable end as shown in Fig. 4a is suitably secured in the socket 12a and the clevis end 13a of the socket is received between a pair of lugs 90 attached to the individual counterweight as presently described, the headed pin 'I4 passing through the 'clevis 13a and lugs 90 and being secured therein by the Cotter 9|.

In the present novel counterweight system, the individual counterweights are desirably cast concrete slabs-Illa, each carried by a steel frame comprising at the top and bottom I-beams 92 and 93 and, at the sides, inwardly facing channel bars 94 into which the concrete is grouted as at 95. The channel bars 94 are desirably of slightly less width than the thickness of the slabs so that the edge of the slab forms somewhat of a tongue 96 securedly embedded in the channel bar. For further securement if desired, anchors may project from the channel bars 94 into the concrete body, as is well known in the concrete art and need not be here described. The slab received in one of the frames just described may be made up of a plurality of edge-to-edge slab sections 91 as here shown, or may be cast as 'a monolith, but in either case, desirablythe I- beams 92 and 93` are suitably secured to thel side channel bars 94 so as to provide a frame constituting, with its concrete interior, a single independent counterweight I8 Vfor one of the cables.

In order to guide the counterweights in their vertical movement within a tower I2 or I3 and to prevent lateral joint or relative displacement of the counterweights, each tower carries a cage 98 for its respective group of counterweights within which this movement of the counterweights is permitted and limited. In the present embodiment of the drawings, this cage includes four vertical uprights 99 'placed at each corner 5o` of one of the joint counterweight groups. The uprights 99 are advantageously of channel form with the channels facing inwardly toward the counterweights and the two outermost counterweights of a group carry a runner plate |00 xed to the side frame member or channel bar 94 of thecounterweight and which projects laterally beyondgthe counterweight at each side. The outer side of this plate is formed with a vertically extending groove IOI which receives the flange |02 of the cage upright 99 slidingly therein. Runner plate |00 extends at its inner side to lap the margin |03 of the adjacent 'intermediate counterweight and this interconnection is continued throughout the group of counterweights in that every other counterweight has a similar runner plate |04 which laps slidingly one of the margins |03 of each next adjacent counterweight. The `alternate counterweights which do not have the runner plates desirably have face strips |05 fixed to their side frame members 94Y as by rivets |06 `and which terminate short of the side margins |03 to cooperate in providing a track forthe runnerplates of the terweights'which carry the runner plates have four of these plates, twolnearthe top of the coun- 'terweight and two near-the bottom. Thus 'the counterweights themselves desirably provide their own common cage parts movable with the jcounterwe'ights for preventing lateral joint and moving vertically therewith within the xedcage parts 99.

The lugs90 by which the cable is attached to its individual counterweight are each riveted as er k|08 suitably securely attached as by rivets |08a to-thev I-beam 92 of the counterweight, the yflangeof the beam being slotted as at |03b to receive the hanger, as best shown in Fig. 4. At each side of said hanger is conveniently located a pair of open-top boxes |09 into which adjustment counterweight increments may be placed, suchior example as the concrete bricks I |0 when it is desired to add to the weight of a counterweight vIt will be understood that the cage parts 99 that are carried within the towers in iiXed position, within the framework of the tower,'terminate short of the roadway-continuing lower portions'of thetowers, and the counterweights even in. extreme upper position of the lift span never descend lower than the lower ends of the cage parts99.

In the present construction if the groove on the sheave becomes worn it can be re-cut and although this may result in a diameter slightly different from the diameters of the sheaves of the other counterweights, it will have no disturbing effect. Whether the length of the cable be actually increased by stretching or in effect increased by deepening of the groove in the sheave, each individual counterweight by the action of gravity acting independently thereon will seek its own level in the counterweight group 'here shown at |01, to a vertically extending hangnecessary to keep its associated cable taut, the

individual counterweights of a group sliding vertically relatively to each other for such purpose by the sliding interconnections |03 and |04 already described. The counterweights and their rassociati-:1:1 cables may thus be of unequal length without causing the span to get out of level, so long as the drive shaft 48 is common to both ther pinions 24-and 25 and these pinions are of the 'same diameter. Also, when lowering the span and bringing it to rest upon its chairs in the fully closed position, application of the force at the rack on the longitudinal center line of the bridge and at the apex of the triangular connections already described forces the span down until the chairs are seated, the counterbalancing system offering no resistance to this operation. The present construction is therefore markedly self-equalizing.

By the present construction, the life of the cables is materially enhanced, and substantial economy in upkeep and maintenance of the bridge effected.

It will be understood that it is not essential that all features of the present invention be used conjointly, as various combinations and subcombinations may be advantageously employed. Furthermore, the invention is not limited to details of construction shown for purposes of illustration, and such changes may be made as fall within the scope of the claims without departing from the invention.

` we Gaim:

1. In a structure ofthe class described embodying a pair of towers and a lift span carried byand movable vertically between the towers by translation in a vertical plane, the combination -therewith of means for carrying and moving the span including cables, oneend of each cable belng attached to thespan and the other end passing-over a'device at the top portion of one -of the towers to depend freely therefrom and having anindividual counterweight attached kto each cable, wherein a plurality of the counterweights are jointly guided by and independently movable in a cage commonv to` said counterweights, said cage preventing substantial lateral vmovement of the individual counterweights but permitting individual vertical movement and wherem the cage is provided in part by plates Y carriedby alternate counterweights and slidingly 2`0 lapping the common adjacent counterweight.

2. iIn a structureof the class described embodymg a pair of towers and a lift span carried by and movable vertically between the towers by translation in a vertical plane, the `combination vtherewith of means for carrying and moving the in a cage common to said counterweights, said cage preventing substantial lateral movement of the individual counterweights but permitting indlvidual vertical movement and wherein the cage isy provided in part by plates carried by alternate counterweights and slidingly lapping the common adjacent counterweight land carried by Lthe outermost counterweights of a group to slidingly engage cage uprights fixed to the tower.

3; '.In a structure of the class described ernbodying a pair of towers and a lift span carried by `and movable vertically between the towers by translation in va vertical plane, the combination therewith of means for counterbalancing the span including a plurality of cables at each end of the span, one end of each cable being in supporting 'relation to the span and the other -end passing over a sheave carried adjacent the top of the tower at that end, the sheaves being arranged in staggered relation in upper and lower rows on the tower with some of the cables passring over sheaves in the upper row and others passing over sheaves in the lower row, counterweights'individual to each cable and a cage carried by each of the towers common to a plurality of the counterweights at that end of the span, said cage preventing substantial lateral end passing overa device at the top portion` of one of the towers to depend freely therefrom and having an individual counterweight attached to each cable, wherein a plurality of the counterweights are jointly guided by and independently movable in a cage common to said counterweights, said cage preventing substantial lateral movement of the individual counterweights concrete bodies of the counterweights, said bars Y being narrower than the concrete body with and the concrete body being tongued into the channel bars. v

5. In a structure of the class described embodying a pair of towers and a lift span carried by and movable vertically between the towers by translation in a vertical plane,l the combination therewith of means for carrying and moving thespan including cables, one end of each cable being attached to the span and the other end passing over a device at the top portion of one Yof the towers to depend freely therefrom and having an individual counterweight attached to each cable, wherein a plurality of the Counterweights are jointly guided by and independently movable in a cage common to said counterweights, said cage preventing substantial lateral movement of the individual counterweights but permitting individual vertical movement and wherein the cage is provided in part by plates carried by alternate counterweights and slidingly lapping the common adjacent counterweight,

said adjacent counterweight having a vertically extending face strip spaced from each of its vertical edges leaving margins providing tracks for said plates.

6. In a structure of the class described embodying a pair of towers and a lift span carried by and movable vertically between the towers by translation in, a vertical plane, the combination therewith of means for counterbalancing the span including a plurality of cables at each end of the span, one end of each cable being in supporting relation to the span and the other end passing over a sheave carried adjacentthe top yof the tower at that end, the sheaves being arranged in staggered relation in upper and lower rows on the tower with some of the cables passing over sheaves in the upper row and others passing over sheaves in the lower row, the sheaves being arranged in pairs, every other of said pairs being in an opposite row on an axle common to each pair for free rotative movement of each sheave of a pair with respect to the other sheave of said pair, and counterweights individual to each cable, whereby relatively close spacing of the cables is permitted while aording access to the sheaves.

7. In a structure of the class described embodying a pair of towers and a lift span carried by and movable vertically between the towers by translation in a vertical plane, the combination therewith of means for counterbalancing the span including a plurality of cables at each end of the span, one end of each cable being in supporting relation to the span and the other end passing over a sheave carried adjacent the .top of the tower at that end, the sheaves being arranged in staggered relation in upper and lower rows on the tower with some oi the cables passing over sheaves in the upper row and others passing over sheaves in the lower row, counterweights individual to each cable and a cage carried by each of the towers common to a plurality of the counterweights at that end of the span, said cage being provided in part by plates carried by the `counterweights and vertically slidingly lapping an adjacent counterweight.

8. In a structure of the class described embodying a, pair of towers and a lift span carried by and movable vertically between the towers by translation in a vertical plane, the combination therewith of means for counterbalancing the span including .a plurality of cables at each end of thespan, one end of each cable being in supporting relation to the span and the other end passing over a sheave carried adjacent the top of the tower at that end, the sheaves being arranged in staggered relation in upper and lower rows on the tower with some of the cables passing over sheaves in the upper row and others passing over sheaves in the lower row, counterweights individual to less than half of the cables at that end, and a cage carried by each of the towers common to a plurality of the counterweights at that end of the span, said cage comprising cage parts movable with the counterweights and preventing substantial lateral movement of the counterweights but permitting both -common and individual vertical movement of the counterweights.

9. In a structure of the class described embodying a pair of towers and a lift span carried by vand movable vertically between the towers by translation in a Vertical plane, the combination therewith of means for counterbalancing the span including a plurality of cables at each` end of the span,vone end of each cable beingin supporting relation to the span and the other end passing over a sheave carried adjacent the top of the tower at that end, the sheaves being arranged in staggered relation in upper and lower rows on the tower with'some ofthe cables passing over sheaves in the upper row and others passing over sheaves in the lower row, and counterweights individual to less than half of the cables at that end.

10. In a structure of the class described embodying a pair of towers and lift span carried by and movable vertically between the towers by translation in a vertical plane, the combination therewith of two vertically spaced apart rows of sheaves carried by each tower, the sheaves of each row being arranged in horizontally spaced apart pairs and pairs of thel vertically spaced apart rows being staggered whereby to place a'pair of one of the vertically spaced apart rows between a pairrof pairs of the other vertically spaced apart rows, cables, one end of leach cable being attached to the span and the BURTON R. LEFFLER. CLIFFORD E. PAINE. 

